1. Field of the Invention
The present invention relates to provisioning and redundancy for devices in an RFID network.
2. Description of the Related Art
Bar codes containing a Universal Product Code (“UPC”) have become a nearly ubiquitous feature of modern life. The vast majority of products, as well as packages, containers and other elements in the stream of commerce now bear a bar code to allow for convenient tracking and inventory control.
However, bar codes have some drawbacks. Bar codes are “read only,” in that they are merely a printed set of machine-readable parallel bars that cannot be updated. Bar codes cannot transmit information, but instead must be read by a scanner. Bar codes must be scanned within a relatively short distance and must be properly oriented for the bar code to be read.
“Smart labels,” generally implemented by RFID tags, have been developed in an effort to address the shortcomings of bar codes and add greater functionality. RFID tags have been used to keep track of items such as airline baggage, items of clothing in a retail environment, cows and highway tolls. As shown in FIG. 1, an RFID tag 100 includes microprocessor 105 and antenna 110. In this example, RFID tag 100 is powered by a magnetic field 145 generated by an RFID reader 125. The tag's antenna 110 picks up the magnetic signal 145. RFID tag 100 modulates the signal 145 according to information coded in the tag and transmits the modulated signal 155 to the RFID reader 125.
Most RFID tags use one of the Electronic Product Code (“EPC” or “ePC”) formats for encoding information. EPC codes may be formed in various lengths (common formats are 64, 96 and 128 bits) and have various types of defined fields, which allow for identification of, e.g., individual products as well as associated information. These formats are defined in various documents in the public domain. One such document is EPC Tag Data Standards Version 1.1 Rev 1.24 (EPCglobal® 2004), which is hereby incorporated by reference for all purposes.
One exemplary RFID tag format is shown in FIG. 1. Here, EPC 120 includes header 130, EPC Manager field 140, Object class field 150 and serial number field 160. EPC Manager field 140 contains manufacturer information. Object class field 150 includes a product's stock-keeping unit (“SKU”) number. Serial number field 160 is a 40-bit field that can uniquely identify the specific instance of an individual product i.e., not just a make or model, but also down to a specific “serial number” of a make and model.
In theory, RFID tags and associated RFID devices (such as RFID readers and printers) could form part of a network for tracking a product (or a group of products) and its history. However, various difficulties have prevented this theory from being realized. One problem that has required considerable time and energy from RF engineers is the development of lower-cost RFID tags with acceptable performance levels. Inductively-coupled RFID tags have acceptable performance levels. These tags include a microprocessor, a metal coil and glass or polymer encapsulating material. Unfortunately, the materials used in inductively-coupled RFID tags make them too expensive for widespread use.
Capacitively-coupled RFID tags use conductive ink instead of the metal coil used in inductive RFID tags. The ink is printed on a paper label by an RFID printer, creating a lower-cost, disposable RFID tag. However, conventional capacitively-coupled RFID tags have a very limited range. In recent years, RF engineers have been striving to extend the range of capacitively-coupled RFID tags.
In part because of the significant efforts that have been expended in solving the foregoing problems, prior art systems and methods for networking RFID devices are rather primitive. RFID devices have only recently been deployed with network interfaces. Device provisioning for prior art RFID devices is not automatic, but instead requires a time-consuming process for configuring each individual device.
Prior art RFID devices and systems are not suitable for large-scale deployment of networks of RFID devices.
Moreover, many RFID devices and related network devices, such as switches and middleware servers, are deployed in a hostile industrial environment (such as a warehouse or factory) by relatively unskilled “IT” personnel. If a device deployed in one location fails, for example, it may simply be removed and replaced by a new device or a device that was deployed in another location.
Currently, RFID middleware is manually configured. RFID readers are statically paired to RFID middleware under current EPCG1oba1 standards. Moreover, RFID middleware has little to no redundancy. If there is a failure of a middleware server, there is currently no systematic method of determining the failure. Therefore, current methods of failure detection involve expensive IT resources. Worse yet, because there is a one-to-one mapping between middleware servers and groups of RFID readers, if a middleware server goes down the associated readers all go down.
If the RFID device population increases, there is currently no automatic way of provisioning RFID middleware to accommodate the increase. Similarly, if the RFID device population requires middleware assignment change, there is currently no automatic way of changing RFID middleware provisioning. It would be desirable to address at least some of these shortcomings of the prior art.